• Journal of Advanced Marine Engineering and Technology
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• 제17권4호
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• pp.38-48
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• 1993

A study on friction welding of stainless steel bar(SUS431) to chrome molybdenum steel bar(SCM21) was accomplished experimentally through analysis for relations among friction welding conditions, tension test, hardness test, microstructure test and acoustic emission test. The results obtained are summarized as follows ; 1. Through friction welding of SUS431 bar to SCM21 bar, the optimum welding condition by considering on strength and toughness was found to be the range of heating time of 3-5 sec when the number of rotating speed of 2000rpm, heating pressure of 10kg/$mm^2$, and upsetting time of 4 sec. 2. Quantitative ralationship was identified between heating time($T_1$, sec) and tensile strength (${\sigma},\;kgf/mm^2$) of the friction welded joint and the relation equation is $\sigma$=52.62$T_1{^{0.06}}$. 3. Through AE test, quantitative relationship was confirmed between heating time($T_1$, sec) and total AE(N, counts) during welding, and the relation is computed as follows ; N=30413.6$e^{0.06T1}$. 4. It was confirmed that the quantitative ralationship exists between the tensile strength of the welded joints and AE cumulative counts. And the relation is computed as the following ; ${\sigma}$=16.37(ln N)- 116.4. 5. When ONZ=36500-41500 counts by $OT_1Z$=3~5sec, it was identified by experiment that the range of welded joint tensile strength is 55.6-57.7kgf/$mm^2$/ whose joint efficiency is more than 100%, and it was experimentally confirmed that the real-time nondestructive quality(strength) evaluation for the friction welded joints could be possible by acoustic emission technique.

• 농약과학회지
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• 제6권3호
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• pp.166-174
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• 2002

정량적인 분자 구조와 물리-화학적인 성질 사이의 상관관계(QSAR)식을 이용하여 약효성을 예측하고 새로운 농약을 탐색하거나 개발하는데 있어서 효율적인 수단으로 활용되는 QSAR 기법의 발전 과정과 자유 에너지 직선관계(LFER)에 관한 기본 개념을 위시한 QSAR 기법의 목적과 유용성 그리고 장단점과 활용 상 제한점 등에 관한 일반적인 내용에 대하여 간략하게 논의하였다.

• Archives of Pharmacal Research
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• 제23권6호
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• pp.579-584
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• 2000

To explore the effect of substituents' on phenyl motif on sulfonyl function of novel anticancer 4-phenyl-1-benzenesulfonylimidazolidinones (1), electron donating or withdrawing sub-stituents were introduced at 3 or 4-position and the analogs were tested against human lung (A549) and colon (HCT-15) cancer cell lines. Quantitative structure activity relation-ship of the 4-substituted series shows that only STERIMOL L values are well correlated. The increment of substituent's volume enhances the activity against both cell lines. The small substituent at 3-position additionally increases the activity. However naphthyl group in place of phenyl reduces the activity, Therefore the phenyl motif with sterically large substituent at 4-position and small substituent at 3-position may be important for their activity. Integration of these substituents' effects into the structural design led to discover the more potent analog, 4-phenyl-1-(N-acetylindoline-5-sulfonyl) imidazolidinone (1n).